Seoul, June 29 : South Korea's Unification Ministry held a hearing on Monday to give two North Korean defector groups a final chance to explain before going ahead with a decision to revoke their operation permits for sending propaganda leaflets into Pyongyang. The hearing came weeks after the Ministry decided to file a criminal complaint with police against Fighters for a Free North Korea and Kuensaem groups and revoke their business permits for their sending of leaflets into the North, reports Yonhap News Agency. "We held a hearing today on Fighters for a Free North Korea and Kuensaem," the Ministry said in a statement. "After checking whether there are any additional documents they need to submit, we will proceed with revocation and other related procedures." Kuensaem officials, including its head Park Jung-oh, a North Korean defector, attended the hearing, but Fighters for a Free North Korea, run by his brother Park Sang-hak, sent no one to the meeting, according to the Ministry. The Ministry's revocation of their business permits could make it hard for the groups to raise money needed for their operations and activities as donors would not be eligible for various tax benefits, said the Yonhap News Agency report. The campaign to scatter leaflets has recently emerged as a major source of cross-border tensions since Pyongyang called it a violation of an inter-Korean summit agreement in 2018 and threatened to take a series of retaliatory steps against South Korea unless it fails to stop such activity. North Korea later called South Korea an "enemy" and blew up an inter-Korean liaison office in its border town of Kaesong over the issue. North Korean defectors and anti-Pyongyang activists have for years sent a large number of leaflets via giant balloons, criticizing North Korean leader Kim Jong-un and his ruling family. Fighters for a Free North Korea and Kuensaem consisting of defectors are among the most active groups in sending the leaflets. On Friday, police raided the offices of the two groups and secured documents and devices. /IANS